The objective of this longitudinal study is to assess both the short term and long term impact health of normative transitions, stresses, and change in the individual's social context and in the broader sphere of social change. The sample, interviewed 5 times over a ten-year period, consisted at baseline of high school seniors, newlyweds, middle-aged parents facing the departure of their youngest child, and persons facing retirement. More specifically, the study is concerned with the social and personal resources influencing the continuing transactions between life experiences and mental health among adults at different points along the life course. Models of stress, transitions, mental health, and commitment will direct an interdisciplinary effort to capture the complexities of the adaptive process. The study design includes: a) frequent in-depth assessments, b) the innovative use of transitions as a sampling base; and c) a variant of the longitudinal sequential analytic strategy. The design focuses particular attention on two transitions: entrance into family and work roles, and entrance into the retirement years. The occurrence over the course of the study, of a number of major social changes affecting the lives of the people being investigated, provides the further opportunity to evaluate the influence of sociohistorical factors on mental health. From an applied perspective, the study is concerned with the prevention and amelioration of mental illness. By identifying alternative pathways to adaptation within a life span sample of non-elite men and women, a better understanding of mental health as a dynamic, interactive process is provided.